Class survey is currently at 2,283 responses (!)
I’ll be doing some cleanup this week and then sharing it with you all over the weekend.
Be on the look out for another survey analysis assignment.
We’ve only got around 1/3rd of your grade accounted for so far, so don’t get complacent.
Pay attention to your R script. You should be submitting a .R file with the code you used to answer your questions. Not a screenshot.
We’ll be going back over the chapter 6 material we covered before the break.
The (arithmetic) mean or average of a variable is the sum of every element divided by the number of observations
The standard deviation of a measure of dispersion. It tells us how much things vary around the mean.
We can “mean-center” a variable by subtracting its mean from each observation. Then we can divide each observation by the standard deviation. This will give us a variable with a mean of zero and standard deviation of 1. (We’ll often refer to this standardized variable as “Z” or a “Z-score”.)
\[ \text{Z score} = \frac{\text{Deviation from the mean}}{\text{Standard Deviation}} \]
\[ \text{Z score} = \frac{\text{Deviation from the mean}}{\text{Standard Deviation}} = \frac{x - \mu}{\sigma} \]